DIMOCK, Pa. — Pat Farnelli says there’s something in the water at her house. The last time she drank it, she says she vomited four times. It’s made her children sick, too.

Like her neighbors in this rural community 15 miles south of the New York border, Farnelli signed a lease with a major natural gas driller to explore a potentially lucrative formation beneath her land. Now Farnelli and others are plaintiffs in a lawsuit that alleges Houston-based Cabot Oil & Gas Corp. polluted their wells with methane gas and other contaminants, destroying the value of their homes and threatening their health.

A Cabot spokesman said the lawsuit, filed late Thursday in federal court in Scranton, was without merit.

At a news conference Friday to announce the suit, residents described an ordeal that began shortly after Cabot started drilling near their homes. The water that came out of their faucets suddenly became cloudy and discolored, and it smelled and tasted foul.

Then, on New Year’s Day, a resident’s water well exploded, prompting a state investigation that found Cabot had allowed combustible gas to escape into the region’s groundwater supplies.

“They were never told that this was even a possibility,” said Alan Fuchsberg, an attorney for the plaintiffs.

More than a dozen families have filed suit, asking for an environmental cleanup, medical monitoring and money damages in excess of $75,000 each.

The state Department of Environmental Protection has determined that 13 wells were polluted, signing a consent decree with Cabot earlier this month in which the company agreed to pay a $120,000 fine, take steps to improve its drilling operations and restore or replace the affected water supplies.

Pennsylvania regulators, citing three chemical spills at a single well site in Dimock, in September halted Cabot’s use of a drilling technique that uses liquids to fracture rock and release natural gas. Cabot was permitted to resume hydraulic fracturing or “fracking” several weeks later after DEP said the company took steps to prevent a recurrence. The spills are cited in the residents’ lawsuit.

Cabot spokesman Ken Komoroski said Friday that the company has not admitted to polluting residents’ wells. He said Cabot believes the high levels of methane gas that have been detected in the wells might be naturally occurring. He said a company investigation continues.

“On one hand, if Cabot caused the methane contamination, certainly it’s understandable why everyone is upset and Cabot will address that situation,” he said. “But I wonder how they’ll feel if at some point it’s proven that Cabot didn’t cause it, that all this anger and frustration has been based on a false premise. And we just don’t know yet.”

Cabot is among a slew of exploration companies that are drilling in the Marcellus shale, a layer of rock deep underground that experts say holds vast stores of largely untapped natural gas. The company began approaching homeowners in Dimock in 2006, promising fat royalty checks and a hassle-free, environmentally friendly operation, plaintiffs said. Instead, residents have been exposed to “combustible gases, hazardous chemicals, (and) threats of explosions and fires,” the suit said.

Some residents also said the company pressured them into signing leases, telling them that all of their neighbors had already signed and that the company would be removing the gas from underneath their properties anyway.

Cabot has drilled at least 62 gas wells within a 9-square-mile tract of land in Dimock, according to the suit. Lawyers say the company has plans for at least 60 more.

Craig Sautner, 56, signed a lease with Cabot shortly after buying his house in the spring of 2008 for $150,000. He said his well has since been contaminated by methane gas and unknown pollutants that discolored his water and made it smell like a “fishy pond.” He now gets his water from a large portable tank in the garage.

“You’re paying a mortgage on a house that’s completely worthless. I work every day, busting my hump just to pay the mortgage and I can’t even sell my house,” said Sautner, a father of two.